73 lines
5.5 KiB
Markdown
73 lines
5.5 KiB
Markdown
---
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summary: "Running the gateway as a child process of the macOS app and why"
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read_when:
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- Integrating the mac app with the gateway lifecycle
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---
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# Clawdis gateway as a child process of the macOS app
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Date: 2025-12-06 · Status: draft · Owner: steipete
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Note (2025-12-19): the current implementation prefers a **launchd LaunchAgent** that runs the **bundled bun-compiled gateway**. This doc remains as an alternative mode for tighter coupling to the UI.
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## Goal
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Run the Node-based Clawdis/clawdis gateway as a direct child of the LSUIElement app (instead of a launchd agent) while keeping all TCC-sensitive work inside the Swift app/broker layer and wiring the existing “Clawdis Active” toggle to start/stop the child.
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## When to prefer the child-process mode
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- You want gateway lifetime strictly coupled to the menu-bar app (dies when the app quits) and controlled by the “Clawdis Active” toggle without touching launchd.
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- You’re okay giving up login persistence/auto-restart that launchd provides, or you’ll add your own backoff loop.
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- You want simpler log capture and supervision inside the app (no external plist or user-visible LaunchAgent).
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## Tradeoffs vs. launchd
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- **Pros:** tighter coupling to UI state; simpler surface (no plist install/bootout); easier to stream stdout/stderr; fewer moving parts for beta users.
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- **Cons:** no built-in KeepAlive/login auto-start; app crash kills gateway; you must build your own restart/backoff; Activity Monitor will show both processes under the app; still need correct TCC handling (see below).
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- **TCC:** behaviorally, child processes often inherit the parent app’s “responsible process” for TCC, but this is *not a contract*. Continue to route all protected actions through the Swift app/broker so prompts stay tied to the signed app bundle.
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## TCC guardrails (must keep)
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- Screen Recording, Accessibility, mic, and speech prompts must originate from the signed Swift app/broker. The Node child should never call these APIs directly; route through the app’s node commands (via Gateway `node.invoke`) for:
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- `system.notify`
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- `system.run` (including `needsScreenRecording`)
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- `screen.record` / `camera.*`
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- PeekabooBridge UI automation (`peekaboo …`)
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- Usage strings (`NSMicrophoneUsageDescription`, `NSSpeechRecognitionUsageDescription`, etc.) stay in the app target’s Info.plist; a bare Node binary has none and would fail.
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- If you ever embed Node that *must* touch TCC, wrap that call in a tiny signed helper target inside the app bundle and have Node exec that helper instead of calling the API directly.
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## Process manager design (Swift Subprocess)
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- Add a small `GatewayProcessManager` (Swift) that owns:
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- `execution: Execution?` from `Swift Subprocess` to track the child.
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- `start(config)` called when “Clawdis Active” flips ON:
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- binary: host Node running the bundled gateway under `Clawdis.app/Contents/Resources/Gateway/`
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- args: current clawdis entrypoint and flags
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- cwd/env: point to `~/.clawdis` as today; inject the expanded PATH so Homebrew Node resolves under launchd
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- output: stream stdout/stderr to `/tmp/clawdis-gateway.log` (cap buffer via Subprocess OutputLimits)
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- restart: optional linear/backoff restart if exit was non-zero and Active is still true
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- `stop()` called when Active flips OFF or app terminates: cancel the execution and `waitUntilExit`.
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- Wire SwiftUI toggle:
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- ON: `GatewayProcessManager.start(...)`
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- OFF: `GatewayProcessManager.stop()` (no launchctl calls in this mode)
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- Keep the existing `LaunchdManager` around so we can switch back if needed; the toggle can choose between launchd or child mode with a flag if we want both.
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## Packaging and signing
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- Bundle the gateway payload (dist + production node_modules) under `Contents/Resources/Gateway/`; rely on host Node ≥22 instead of embedding a runtime.
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- Codesign native addons and dylibs inside the bundle; no nested runtime binary to sign now.
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- Host runtime should not call TCC APIs directly; keep privileged work inside the app/broker.
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## Logging and observability
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- Stream child stdout/stderr to `/tmp/clawdis-gateway.log`; surface the last N lines in the Debug tab.
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- Emit a user notification (via existing NotificationManager) on crash/exit while Active is true.
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- Add a lightweight heartbeat from Node → app (e.g., ping over stdout) so the app can show status in the menu.
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## Failure/edge cases
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- App crash/quit kills the gateway. Decide if that is acceptable for the deployment tier; otherwise, stick with launchd for production and keep child-process for dev/experiments.
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- If the gateway exits repeatedly, back off (e.g., 1s/2s/5s/10s) and give up after N attempts with a menu warning.
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- Respect the existing pause semantics: when paused, the broker should return `ok=false, "clawdis paused"`; the gateway should avoid calling privileged routes while paused.
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## Open questions / follow-ups
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- Do we need dual-mode (launchd for prod, child for dev)? If yes, gate via a setting or build flag.
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- Embedding a runtime is off the table for now; we rely on host Node for size/simplicity. Revisit only if host PATH drift becomes painful.
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- Do we want a tiny signed helper for rare TCC actions that cannot be brokered via the Swift app/broker?
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## Decision snapshot (current recommendation)
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- Keep all TCC surfaces in the Swift app/broker (node commands + PeekabooBridgeHost).
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- Implement `GatewayProcessManager` with Swift Subprocess to start/stop the gateway on the “Clawdis Active” toggle.
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- Maintain the launchd path as a fallback for uptime/login persistence until child-mode proves stable.
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